Different methods for the determination of gestodene, and cyproterone acetate in raw material and dosage forms

Four new precise accurate and selective methods have been developed for the determination of gestodene (I) and cyproterone acetate (II). The first method (A) depends on reaction of(I) and (II) with isoniazide in an acid medium and the colored products were measured at 378 and 400 nm, respectively. The second method (B) depends on the reaction of (I) and (II) with tetrazolium blue in an alkaline medium and the colored products were measured quantitatively at 515 and 520 nm, respectively. The optimum conditions for the analysis were studied. Both methods determined gestodene (I) in concentration range from 4 to 24 mug ml(-1) with mean percentage recoveries 99.54% +/- 1.20 and 99.63% +/- 1.89 for method A and B, respectively. For cyproterone acetate, the concentration ranges were 4-36 and 8-40 mug ml(-1) with mean percentage recoveries 99.94% +/- 1.19 and 99.23% +/- 2.00 for methods A and B, respectively. The third method (C) depends on the quantitative evaluation of (I) and (II) densitometrically using dichloroethane:methanol:water (95:5:0.2) as mobile phase and the chromatogram were scanned at 247 and 281 nm, respectively. Method (C) determines (I) and (II) in concentration ranges from 0.2 to 1.6 and 0.1-0.7 mug mul(-1) using Hamilton syringe 10 mul, with mean percentage recoveries 99.94% +/- 1.19, and 99.82% +/- 1.75, respectively. The fourth method (D) is a first derivative one depends on measuring the D-1 value at 303 nm for (II) only in concentration range 10-20 mug ml(-1) with mean percentage recoveries 99.95% +/- 1.49. (C) 2001 Elsevier Science B.V. All rights reserved.